Washington, the Evergreen State. Just do not go east of the Cascades and that is true. Much of the state, especially some of the prime agricultural areas get between 5 and 10 inches of rain a year. How is this possible? The Columbia, Yakima, and Snake River Watersheds.
http://irrigation.wsu.edu/Content/Washington-Irrigation.php
http://choosewashingtonstate.com/research-resources/about-washington/climate-geography/
Steven Lawrence Pictures 